すばる prime focus spectrograph (pfs)blue 3800-6700 2300 red 6500-10000 3000 nir 9700-13000 4400...

2012年8月9日光学赤外線天文連絡会シンポジウム「2020年に向けてのロードマップ」 @国立天文台三鷹

すばる Prime Focus Spectrograph (PFS) 菅井肇 (Kavli IPMU)

実行グループ (PI 村山斉 Kavli IPMU)

Prime Focus Spectrograph (PFS)

1. What is PFS ?

2. Science targets

3. Why on Subaru ?

4. Challenges in PFS

5. Each component

6. Efficiency & sensitivity estimates

7. Major milestones

8. Summary

1. What is Prime Focus Spectrograph (PFS) ?

Optical + NIR Multi-object fiber spectrograph

- Number of fibers: 2400

600 per Spectr. X 4 Spectrographs

- Fiber core diameter 128mm

Microlens attached to fiber input edge

fiber input F/2.2 -> F/2.8 (1”.1 diameter per fiber)

- Field of view: 1.3 deg

- Wavelength: 0.38 - 1.3 μm

概要

[Sugai et al. SPIE]

1. What is PFS ?


- Each spectrograph: 3-color-arm design

Arm Coverage[A] Resolution[l/dl]

------------------------------------------------------

Blue 3800-6700 2300

Red 6500-10000 3000

NIR 9700-13000 4400

-------------------------------------------------------

Spectrograph collimator F/2.5, camera F/1.1

Detector pixel 15mm (2Kx4K x 2 FDCCDs for each Blue/Red arm, 4Kx4K HgCdTe(1.7mm cutoff) for NIR arm)

movie movie with sound

How the system works

../obayashi/check0702b.wmvPFSintro.m4v

2. Science targets

Cosmology

Galactic Archaeology Galaxy/AGN evolution

See arXiv:1206.0737 “Extragalactic science and cosmology with Subaru PFS” Ellis et al. (2012)

Credit: Gen Chiaki, Atsushi Taruya

Image: Belokurov et al.

SF rate figure: Hopkins & Beacom

9.3 h-3 Gpc3 in 0.8

Strengths of Subaru Telescope

Large Field of View e.g., Suprime Cam (Hyper Suprime Cam, Prime Focus Spectrograph) Platescale (arcsec mm-1) ∝1/f prime focus (rigid tel. structure)

Excellent Image Quality e.g., Kyoto 3DII (PI instr.: IFS,FP,etc.) + AO188 in optical wavelength mirror surface, dome shape, rigid structure, tel. tracking

3. Why on Subaru ?


- Bright telescope F-ratio of 2.2

- Bright camera F-ratio of 1.1

- Quick & accurate reconfiguration of fiber

positioners

Comparison with other optical multi-fiber spectrographs

( )


- Bright telescope F-ratio of 2.2

Use of microlens

Transformation of F-ratio from 2.2 2.8

- Bright camera F-ratio of 1.1

Use of double Schmidt corrector

- Quick & accurate reconfiguration of fiber positioners

Uses of new-type high-precision positioner and wide-field

metrology camera

5. Each component

- Microlens + Fiber

- Fiber positioner

- Spectrograph

- Metrology camera

Sharing Wide Field Corrector with HSC

PFS case:

Optical interface with Wide Field Corrector

Field element

= 52-mm thickness flat plate

substitutes for filter + dewar window

http://www.eso.org/sci/facilities/eelt/fp7-elt-pub/

wfi_workshop/pdffile/SMiyazaki.pdf

Hyper Suprime-Cam

(HSC)

Wide Field Corrector (WFC)

国内の他の計画との関連

Light from telescope through WFC & Field element

to microlens + fiber

Microlens at fiber entrance

Transforms input f-ratio (F/2.2 F/2.8)

(1) to reduce light loss caused by over-filling

acceptance angle of fiber

(2) to ease difficulties of spectrograph design

Molding a suitable microlens out of glass

glass - variety of refractive-index selection

molding - aspheric surface

Fiber core

Challenge for fast F-ratio with Microlens

600 mm

Fiber experiment/development

[de Oliveira et al. SPIE]

Careful measurements of

fiber characteristics,

including F-ratio degradation

1.3°Field of View

Cobra Positioner Patrol Area

(9.5 mm dia.)

Theta Stage (2.4 mm

radius)

Phi Stage (2.4 mm

radius)

2400 Cobra Positioners

Cobra Optic Bench

Theta Stage

Phi Stage

Fiber Arm

New type Positioner

Rigid, No inclining

JPL --- started prototype 7-element Cobra development

Fiber Positioner

[Fisher et al. SPIE]

through fiber to spectrograph

0.38-1.3mm: VPH gratings 280 mm diam. each

Resolving power = l/dl ~ 3000

Spectrograph

We build four of these

[Vivès et al. SPIE]

[Gunn et al. SPIE]

No moving parts

Stability, Easier operation

Fiber slit length ~140 mm

(fiber spacing =230 mm)

Spectrograph

Back-illuminated fiber observed by metrology camera

Metrology camera

(2)

Planned to be located in

Cassegrain container

Magnification ~0.0415

Camera aperture size ~130 mm

Detector 120M 2.2mm-pixel CMOS

(diffraction-limited image quality)

Here

645 mm

“Directly” seen and taken with one shot

[Wang et al. SPIE]

6. Efficiency & sensitivity estimates

6.1 Total efficiency estimates

6.2 Signal-to-noise ratio estimates

Efficiency & S/N estimates Taking Wide Field Corrector (WFC) distortion into consideration

Fiber diam.=1”.13

at center

1”.03

at 0.675 deg

Non-telecentricity, vignetting, residual chromatic aberration also considered

Total efficiency for field center at zenith Includes everything from sky to detector (0”.64 seeing at 730nm) & aperture effect

80

60

40

20

0

400 500 600 700 800 900 1000 1100 1200 1300 nm

Total efficiency for field corner at el=30deg

Signal-to-noise ratio estimates

Balanced S/N ratio over wide wavelength range

7. Major milestones (events)

Endorsement by Japanese community 2011 Jan

MOU between NAOJ and Kavli IPMU 2011 Dec

Project CoDR (Conceptual Design) 2012 Mar

Project PDR (Preliminary Design) 2013 Jan

Project CDR (Critical Design) 2013 Dec

SIR/TRR (System Integration /Test Readiness) 2016 Feb

ORR (Operational Readiness) 2016 Nov

First Light (Engineering) 2017 Jan

現在想定しているスケジュール

暗黒エネルギーの性質をLSST、Euclidなどの巨大計画に迫る精

度で、彼ら以前に測定する。z~1–2の今までにない大規模な銀河

データ、超遠方の銀河の分光データ、銀河系内星の6次元位相空

間分布を得る。

なお、地上望遠鏡による多天体ファイバ分光器はBigBOSSや

4MOSTをはじめ口径4メートルクラス望遠鏡で計画されているが、

PFSでは8メートルの口径を活かし高品質のより遠方の銀河まで

を含むデータで対抗する。(なお、4メートルクラスでは可視光のみ)

またTMT時代にはtarget selectionにHSC+PFSが不可欠となる。

海外の類似計画との差別化

8. PFS Summary


- On Subaru prime focus (8.2m; F/2.2)

- Target sciences:

- cosmology, Galactic Archaeology, galaxy/AGN evolution

- Basic parameters

- Number of fibers 2400 (600 x 4)

- Field of view: 1.3 deg

- Wavelength: 0.38 - 1.3 μm

- Spectral resolution: l/dl~3000

- Now in Preliminary Design phase (PDR ~2013 Jan)

- Conceptual Design Reveiw succeeded 2012 March

2nd General Collaboration Meeting @ Tokyo 2012 Jan

PFSポータルサイト http://sumire.ipmu.jp/en/2652 (より一般向けのwwwも近日公開) 技術的なより詳細 http://pfs.ipmu.jp/factsheet/

関連ホームページ
http://sumire.ipmu.jp/en/2652http://pfs.ipmu.jp/factsheet/

すばる prime focus spectrograph (pfs)blue 3800-6700 2300 red 6500-10000 3000 nir 9700-13000 4400...

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